The present invention relates to a suspension load beam configured to carry a transducer head. More particularly, the present invention relates to a suspension load beam having thermal insulation layers that reduce structural distortion of the suspension load beam in response to environmental temperature changes.
Disc drives are data storage devices that store digital data in magnetic form on a rotating disc. Modern disc drives comprise one or more rigid information storage discs that are coated with a magnetizable medium and mounted on the hub of a spindle motor for rotation. Data is read from and written to a plurality of concentric circular tracks on the discs by transducer heads (“read/write heads”) that are carried by sliders placed in close proximity to the disc surfaces. Each slider is attached through a gimbal system to a distal end of a suspension load beam. The proximal end of the suspension load beam is attached to an actuator arm that rotates to move the slider to a desired position relative to the associated disc surface.
During a write operation sequential data is written onto the disc track, and during a read operation the head senses the data previously written onto the disc track and transfers the information to an external environment. Important to both of these operations is the accurate and efficient positioning of the head relative to the center of the desired track on the disc (i.e., track following).
Head positioning within a desired track is dependent on head-positioning servo patterns, which are patterns of data bits recorded on the disc surface that are used to maintain optimum track spacing and sector timing. The servo patterns or information can be located between the data sectors on each track of a disc (“embedded servo”), or on only one surface of one of the discs within the disc drive (“dedicated servo”).
The servo patterns are typically recorded on the magnetizable medium of a target disc by a servo-track writer (“STW”) assembly during the manufacture of the disc drive. One type of STW assembly records servo pattern on the discs following assembly of the disc drive. The STW assembly attaches directly to a disc drive having a disc pack where the mounted discs on the disc pack have not been pre-recorded with servo pattern. The STW essentially uses the drive's own read/write heads to record the requisite servo pattern directly to the mounted discs. An alternative method for servo pattern recording utilizes a separate STW assembly having dedicated servo recording transducers or heads for recording servo pattern onto one or more discs. The dedicated servo recording heads can be used to record servo information to a number of discs simultaneously, which are subsequently loaded into the disc drive for use.
Recent efforts within the disc drive industry have focused on developing cost-effective disc drives capable of storing more data onto existing or smaller-sized discs. One potential way of increasing data storage on a disc surface is to increase the recording density of the magnetizable medium by increasing the track density (i.e., the number of tracks per inch). Increased track density requires more closely-spaced, narrow tracks and therefore enhanced accuracy in the recording of the servo-patterns onto the target disc surface.
Thermal distortion of the suspension load beam can contribute to errors in the positioning of the servo-patterns relative to the target disc. The principle of thermal expansion states that essentially all solids expand in volume when the temperature is raised. When the temperature is increased, the average distance between atoms increases, which leads to an expansion of the whole solid body.
During disc drive or STW operation, temperature gradients in the suspension load beam continuously change over time. These changes are due in part to varying wind currents around the suspension load beam and the varying heat contributions of components of the device. The resultant thermal distortions to the structure of the suspension load beam cause the position of the transducer head to deviate from the desired position, which affects the accuracy at which the servo-patterns can be written. As a result, such thermal distortions can limit the track density of the recording medium and can introduce undesirable repeatable runout that must be compensated for by the disc drive during track following (e.g., data read and write operations).
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages.